Blythe — Historic Preservation

Last reviewed: July 1, 2026

Overview

Blythe’s zoning ordinance does not create a standalone “Historic Preservation” chapter. Instead, historic resources show up in three places: the downtown-oriented D-O overlay’s design review process, floodplain standards that define and treat a “historic structure,” and SB 9’s two‑unit provisions that exclude mapped or designated historic resources from ministerial approval. Where the ordinance is silent (e.g., how a “city landmark” is designated), you must verify locally.

How Blythe’s zoning touches historic resources

D‑O Downtown Overlay (Design Review Area)

• Purpose and where it applies: The D-O overlay identifies downtown “review areas” for compliance with adopted redevelopment plans and the city’s Downtown Design Standards and Architectural Guidelines; boundaries are set on the official zoning map. Verify the mapped limits with the City of Blythe planning department. §17.06.061–.064
• What it regulates: In the D-O overlay, all new uses/structures, changes of use, and any exterior modification are subject to approval by the Design Review Committee to ensure conformance with the downtown design program. §17.06.062; §17.64.064–.065
• Permitted uses: Uses are those of the underlying zone (e.g., see Blythe Zoning and Blythe Land Use); the overlay adds review but does not change use permissions. §17.06.064
• Key dimensional standards: None unique to D‑O; base development standards of the underlying district apply. §17.06.064
• Process highlights: The committee reviews site plans, elevations, landscape, and signage; it must act within a 30‑day window after materials are deemed adequate. §17.64.064–.065

Areas of Special Flood Hazard (Chapter 17.29)

• Purpose and where it applies: Flood hazard regulations apply within FEMA‑mapped special flood hazard areas adopted by reference in the city’s Flood Insurance Study. §17.29.030(A)–(B)
• Why it matters for historic resources: The code defines a “historic structure” (NRHP‑listed or eligible; contributor to a registered or eligible district; listed on a state inventory; or listed on a certified local inventory). §17.29.020 (definition of Historic structure)
• Special treatment:
  • The definition of “substantial improvement” excludes alterations of a “historic structure,” if the work does not preclude continued historic designation. §17.29.020 (definition of Substantial improvement)
  • A floodplain variance may be issued for repair or rehabilitation of a “historic structure” if the work does not jeopardize the structure’s historic designation and the variance is the minimum needed to preserve its character. §17.29.060(B)(2)
• Permitted uses and dimensional standards: Governed by the underlying zoning; floodplain provisions add constraints (e.g., development limits in floodways) that apply regardless of use category. §17.29.050(F)

Single‑Family Zones and SB 9 Two‑Unit Housing (Chapter 17.33A)

• Where it applies: Ministerial two‑unit projects occur in single‑family zones (SPR, RR, A, R‑E, R‑L‑1, R‑L‑72, R‑L‑1‑72) if all eligibility criteria are met. §17.33A.010–.020(A), (B)
• Historic‑resource exclusion: Sites in a historic district, on the State Historic Resources Inventory, or designated/listed as a city landmark or historic property/district under a city ordinance are ineligible for SB 9 ministerial approval. §17.33A.020(C)(1)
• Practical effect: On such historic sites, two‑unit proposals are not eligible for the SB 9 ministerial track. Other entitlement paths may still exist under regular variances and exceptions or discretionary review, subject to California housing laws, but these are outside this page’s scope.

Decision‑relevant standards and review triggers

Note: Within the D‑O overlay, signage is part of design review; coordinate early with Blythe Signage standards and downtown guidelines. §17.64.064(D)

Information Gaps

• City landmark/district designation process and maps: Not found in retrieved materials. Verify with the jurisdiction.
• List or map of locally designated historic properties: Not found in retrieved materials. Verify with the jurisdiction.
• Any citywide Historic Preservation Overlay District or commission beyond D‑O: Not found in retrieved materials.

Checklist

• Confirm whether your parcel lies in the D‑O overlay; if yes, plan for design review and prepare site, elevation, landscape, and signage plans. §17.06.062; §17.64.064
• Determine if your building is a defined “historic structure” under floodplain rules (NRHP/state/local certified inventory). §17.29.020
• If in a flood hazard area, assess whether planned work would be a “substantial improvement” or qualifies for the historic‑structure exclusion. §17.29.020
• If preservation requires deviation from flood standards, evaluate a floodplain variance for a historic structure and document why it’s the minimum necessary. §17.29.060(B)(2)
• For SB 9 two‑unit concepts, confirm the site is not in a historic district or a city landmark/historic property; otherwise SB 9 ministerial approval is unavailable. §17.33A.020(C)(1)
• Align site design with base development standards and parking in the underlying zone; D‑O adds review but not new dimensional standards. §17.06.064
• If exterior signage or landscaping changes are proposed downtown, include them in your design review submittal to avoid delays. §17.64.064

Risks & Ambiguities

Plain-English Summary

Blythe doesn’t have a single “historic preservation” chapter, but three parts of its zoning matter: downtown properties in the D‑O overlay need design review for exterior changes; floodplain rules define “historic structure” and offer limited relief to preserve it; and SB 9 two‑unit projects can’t use ministerial approval on sites that are locally or state‑recognized as historic. If your building might be historic, verify its status and where you’re mapped, and plan your submittals accordingly.

Source References

• Title 17, §17.06.061–.064 (D‑O overlay purpose, development manner, and map notation)
• Title 17, §17.64.064–.065 (Design Review Committee scope, submittals, and 30‑day action)
• Title 17, §17.29.020 (Definitions: Historic structure; Substantial improvement exclusion)
• Title 17, §17.29.050(F) (Floodway development standards); §17.29.030 (FEMA FIS adoption)
• Title 17, §17.29.060(B)(2) (Variance for repair/rehabilitation of historic structures)
• Title 17, §17.33A.010–.020, especially §17.33A.020(C)(1) (SB 9 eligibility; historic/landmark exclusion)

Retrieved passages

• Blythe Zoning Code (§ 1) Medium relevance show source text
• Blythe Zoning Code (chapter and) Medium relevance show source text
• Blythe Zoning Code (Section 17.64.060) Medium relevance show source text
• Blythe Zoning Code Medium relevance show source text
• CBC § 5020.1 (Section 5020.1) Medium relevance show source text
• Blythe Zoning Code (chapter which) Medium relevance show source text
• Blythe Zoning Code (Section 17.29.060) Medium relevance show source text
• Blythe Zoning Code (chapter are) Medium relevance show source text

Cited sections

• Title 17, §17.06.061–.064 (D‑O overlay purpose, development manner, and map notation) (Title 17)
• Title 17, §17.64.064–.065 (Design Review Committee scope, submittals, and 30‑day action) (Title 17)
• Title 17, §17.29.020 (Definitions: Historic structure; Substantial improvement exclusion) (Title 17)
• Title 17, §17.29.050(F) (Floodway development standards); §17.29.030 (FEMA FIS adoption) (Title 17)
• Title 17, §17.29.060(B)(2) (Variance for repair/rehabilitation of historic structures) (Title 17)
• Title 17, §17.33A.010–.020, especially §17.33A.020(C)(1) (SB 9 eligibility; historic/landmark exclusion) (Title 17)
• Blythe_ZoningCode.md

• Official Blythe code library